Comparison of observed Ca xix and Ca xviii relative line intensities with current theory

Jordan, C.; Veck, N. J.

doi:10.1007/bf00151148

Cited by 16 publications

(1 citation statement)

References 21 publications

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“…Clearly, experimental data are required to determine which theoretical calculations are correct. Some tests have come from experimental observations of the solar corona (O and Ne [59]; Ne [84]; Ca [46]) and tokamak plasmas (S, C1, Ar [47];…”

Section: Existing Data Calculations and Applicationsmentioning

confidence: 99%

A study of diagnostic x-ray lines in heliumlike neon using an electron beam ion trap

Wargelin

1993

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Heliumlike ions play an extremely important role in X-ray astrophysics because of their emissivity and because the relative intensities of their emission lines can be used to infer physical characteristics of X-ray emitting plasmas, including temperature, electron density, and ionization balance. In der to properly apply these diagnostics, accurate atomic data are required, including cross sections for collisional excitation and ionization, radiative rates, and the wavelengths and strengths of satellite lines. Although theoretical atomic models have been created to estimate many of the rates and cross sections involved, very few experimental results are available for comparison with theoretical predictions. This thesis describes an experimental study of heliumlike neon using an electron beam ion trap, a device specifically designed to study X-ray emission from highly charged ions. Using a low-energy X-ray spectrometer designed and built for this experiment, electron impact excitation cross sections and dielectronic satellite strengths were measured for all significant n = 2_ 1 emission lines in He-like and Lilike Ne over a range of energy extending from well below the direct excitation threshold of the lines to over fourteen times the threshold energy. The cross section for innershell ionization of Li-like Ne, which excites the He-like forbidden line, was also measured. In addition, the radiative and collisional depopulation rates of the metastable ls2s 3S1 state, which form the basis of the He-like Ne density diagnostic, were determined. Experimental results were generally in agreement with theoretical predictions, although some significant differences were noted, particularly for the wavelengths and resonance strengths of dielectronic satellites. In addition, the excitation cross section for the intercombination line blend was found to be 15% higher than predicted by theory, while the cross section of the forbidden line was 25% higher. Results from the study of innershell ionization and excitation of Li-like Ne were used to distinguish between three widely varying predictions of the fluorescence yield of the primary Li-" like Ka line. The radiative lifetime measurement had a precision of nearly one percent and was found to be in excellent agreement with theoretical predictions.

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Section: Existing Data Calculations and Applicationsmentioning

confidence: 99%

A study of diagnostic x-ray lines in heliumlike neon using an electron beam ion trap

Wargelin

1993

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Diagnostics of Solar and Astrophysical Plasmas Dependent on Autoionization Phenomena

Doschek

1985

Autoionization

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Theoretical Neix line ratios compared to solar observations

Keenan¹,

Tayal²,

Kingston³

1984

Sol Phys

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R-matrix calculations of the 11S -23S and 11S -23p electron excitation rates in He -like Cv, OvII, and Mgxl by Kingston and Tayal are used to interpolate results for NeIx. Adoption of these in emission line strength calculations leads to values for the density-sensitive R ratio very similar to those of Pradhan et al. and Wolfson et al., although the temperature-sensitive G ratios are approximately 10 to 20 % lower than those deduced by these authors. However the present theoretical value of G at the temperature of maximum NeIx emission, G(Tm) = 0.82, is in excellent agreement with those observed by the SMM and P78-1 satellites for the 1980, November5 flare (G= 0.83 _+ 0.01) and nonflaring active regions (G = 0.80 _+ 0.05), respectively.

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Comparison of observed Ca xix and Ca xviii relative line intensities with current theory

Cited by 16 publications

References 21 publications

A study of diagnostic x-ray lines in heliumlike neon using an electron beam ion trap

A study of diagnostic x-ray lines in heliumlike neon using an electron beam ion trap

Diagnostics of Solar and Astrophysical Plasmas Dependent on Autoionization Phenomena

Theoretical Neix line ratios compared to solar observations

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